1. Field of the Invention
The present invention relates to an auto-exposure control method and, more particularly, to a fast and stable auto-exposure control method of a digital image capturing device using an image sensor such as a digital camera, a compact camera module, and the like.
2. Description of the Related Art
Recently, a compact camera module employing an image sensor such as a CCD or a CMOS is installed in a mobile communication terminal to provide a camera function and also actively applied for vehicles to monitor front and rear blind spots.
Thus, algorithms for applying various camera functions such as auto-focusing (AF), auto-white balance (AWB), auto-exposure (AE), and the like, to small cameras are required. In particular, the conventional, known algorithms developed for auto-exposure are largely applied to a dedicated digital still camera system, which may be performed by a processor with a sufficient performance for processing the auto-exposure algorithms. Thus, it is not possible to apply the conventional auto-exposure algorithms to a camera module installed in the mobile communication terminals or in vehicles that do not have a dedicated processor of high performance for image processing due to a cost or size-related problem, and if ever, much time would be taken to determine a proper exposure value because of a huge amount of calculation and the like. Thus, an algorithm for controlling auto-exposure quickly and stably with a smaller amount of calculation is required for a compact camera module applied to the mobile communication terminals or vehicles.